my g-friends white car was parked behind me when i cranked the engine....i revved to 2500 and let it idle a bit.... i looked at the front of her car and it had this black smattering of what i thought was oil but it was dry , kind of powder-like.....it looks like the spray pattern of black spray paint that is almost out.....like it is spitting out the paint.... then i put my finger in front of the exhaust pipe and it got on my finger and almost instantly dried when it hit my finger ..... it was not slick or greasy at all....it feels like a powdery substance.....is this carbon? it is a '73 2L that i got out of another car so who knows what's inside? probably 85000 miles on it..... it also smokes lightly when i'm accelerating...kind of a dark smoke.....that black stuff coming out i presume.

correct. its carbon.

can you tell i'm happy it's NOT oil?!!!!! so what's next.....just keep driving until it blows all out?

thanks...i'm just so happy it's not oil!!!!!!!! should i keep messing with the little screw until it stops spitting out the carbon? i'll check the plugs as well

The screw on the brain only adjusts the mixture at idle...